1. Field of the Invention
The present invention relates to an open showcase in which a display chamber is formed in an insulating wall to display commodities in the display chamber while cooling the commodities. More particularly, it relates to lights in the display chamber.
2. Description of the Related Art
Heretofore, as this type of open showcase, for example, there has been an open showcase 100 disclosed in Patent Document 1 and shown in FIG. 10. FIG. 10 shows a vertical side view of the conventional open showcase 100. In this open showcase 100, cold air is discharged from a discharge port 103 formed in an upper edge of an opening 102 of an insulating wall 101 having a substantially U-shaped section toward a suction port 104 of a lower edge of the opening 102, whereby a cold air curtain is formed in the opening 102. In consequence, the inside of a display chamber 105 surrounded with the insulating wall 101 is cooled to a predetermined temperature. Then, a plurality of fluorescent lamps 108 are attached to a canopy 107 positioned outside the upper edge of the opening 102, opposite side edges of the opening 102 and lower surfaces of front parts of shelves 106 to illuminate the inside of the display chamber 105 and the showcase 100 itself.
[Patent Document 1] Japanese Patent Application Laid-Open No. 5-146346
However, in the conventional open showcase 100, the fluorescent lamps 108 are used as light devices, and the fluorescent lamps 108 are provided on an upper front part of the display chamber 105, the lower surfaces of the shelves 106 disposed in the display chamber 105 and the like, so that there has been a problem that a thermal load is generated in the display chamber 105 owing to the fluorescent lamps 108. A usual fluorescent lamp converts electric energy into visible radiation, infrared radiation and ultraviolet radiation to radiate a visible ray for use as the light. In this case, a thermal loss is generated, and hence there is a problem that the inside of the display chamber 105 is heated by not only the fluorescent lamps themselves but also radiant heat of the fluorescent lamps.
Therefore, in a cooling showcase in which the inside of the display chamber 105 is cooled to the predetermined temperature, a cooling operation is performed in consideration of a thermal load due to the light, so that a cooling efficiency lowers. In consequence, there has been a problem that steep rise of running cost is incurred. Commodities displayed in the display chamber 105 are irradiated with an ultraviolet ray, so that there is a problem that the commodities are adversely affected.
Furthermore, the fluorescent lamps have a problem that flicker is generated owing to use of an alternating current, so that there is a problem that eyes are adversely affected.
In addition, to attach the fluorescent lamps 108 in the display chamber 105, components such as sockets and stabilizers are required. Therefore, in attachment positions, attachment places for not only the fluorescent lamps but also the sockets, stabilizers and the like need to be secured. The fluorescent lamps have to be connected to wires in order to supply power to the lamps. There are problems that assembly operability is deteriorated and that increase of the number of the components and steep rise of production cost are incurred.
In recent years, a thickness of the whole shelves 106 tends to be reduced for a purpose of improving a display efficiency in the display chamber 105. In actual, there is a problem that a thickness dimension of each shelf 106 is limited by the fluorescent lamp provided under the shelf 106.
Moreover, a replacement operation of the fluorescent lamps 108 is forcibly required owing to luminance decrease and light defect caused with elapse of years. Therefore, a user is forced to perform the replacement operation of the fluorescent lamps 108, and the operation disadvantageously becomes laborious. The new fluorescent lamp 108 for replacement needs to be always prepared, and a storage place of the fluorescent lamp 108 needs to be secured. Furthermore, the fluorescent lamp 108 contains mercury, resulting in a problem that the used fluorescent lamp 108 cannot easily be discarded.